a(1) = 1, a(n) = 2*a(n-1) + a([n/2]).

Terms

a(0) =1a(1) =3a(2) =7a(3) =17a(4) =37a(5) =81a(6) =169a(7) =355a(8) =727a(9) =1491a(10) =3019a(11) =6119a(12) =12319a(13) =24807a(14) =49783a(15) =99921a(16) =200197a(17) =401121a(18) =802969a(19) =1607429a(20) =3216349a(21) =6435717a(22) =12874453a(23) =25755025a(24) =51516169a(25) =103044657a(26) =206101633a(27) =412228073a(28) =824480953a(29) =1649011689